Improvements In Or Relating To Well Abandonment and Slot Recovery

Abstract

A rigless method for abandoning a well in which the production tubing ( 7 ) and control lines ( 15 ) are left in place. The production tubing ( 7 ) is perforated at a zone of interest at any position in the well. A settable composition ( 21 ) which is dissolvable in acid is injected through the perforations ( 20 a, 20 b ) into the annulus between the casing ( 5 ) and the production tubing ( 7 ) over the zone of interest and allowed to set. The composition supports the tubing ( 7 ) and secures the control lines ( 15 ) so that they can be cut and milled away to expose the casing. An acid wash is performed to remove all the settable composition and clean the casing ( 5 ) in preparation for a cement bond log to be performed. If the quality of the cement bond is acceptable a cement plug ( 28 ) is deployed. Further cuts in the production tubing ( 7 ) can be made to expose further sections of casing ( 5 ) in the event that the cement bond log is unacceptable.

We claim: 
     
         1 . A method of abandoning a well, the well including a cemented section behind casing in a wellbore and production tubing within the casing at the cemented section, comprising the steps in order:
 (a) perforating the production tubing in the wellbore at a zone of interest at the cemented section at a location;   (b) passing a settable composition, the settable composition being dissolvable in acid, through the perforations into the annulus between the casing and the production tubing over the zone of interest;   (c) allowing the settable composition to set to secure the production tubing to the casing over the zone of interest;   (d) cutting the production tubing at the zone of interest to access the casing at the cemented section;   (e) performing an acid wash to remove the set settable composition over the zone of interest; and   (f) performing a cement bond log to assess the quality of the cement bond at the cemented section over the zone of interest.   
     
     
         2 . The method according to  claim 1  wherein the zone of interest has an upper edge and a lower edge, the lower edge being at a seal within the annulus. 
     
     
         3 . (canceled) 
     
     
         4 . The method according to  claim 1  wherein the zone of interest comprises a length in the range 30 m to 60 m. 
     
     
         5 . The method according to  claim 1  wherein the settable composition is a resin. 
     
     
         6 . The method according to  claim 1  wherein the settable composition is a gel. 
     
     
         7 . The method according to  claim 1  wherein the method comprises at step (b) deploying an injection tool to displace a pre-determined amount of settable composition through the perforations into the annulus. 
     
     
         8 . The method according to  claim 1  wherein the method includes at step (b) passing the settable composition into the annulus as a foam. 
     
     
         9 . The method according to  claim 1  wherein the method comprises at step (a) running a perforating tool through the tubing to the zone of interest. 
     
     
         10 . The method according to  claim 1  wherein the method comprises perforating the tubing using explosive charges. 
     
     
         11 . The method according to  claim 9  wherein the perforating tool is a punch tool. 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . The method according to  claim 1  wherein the method comprises at step (d) providing a tubing cutter to cut a slot through a wall of the production tubing. 
     
     
         17 . The method according to  claim 1  wherein the method comprises deploying a milling tool to mill away the tubing. 
     
     
         18 . The method according to  claim 17  wherein the method comprises milling away the securing settable composition in the annulus between the casing and the tubing. 
     
     
         19 . (canceled) 
     
     
         20 . The method according to  claim 17  wherein the method comprises milling in an upward direction. 
     
     
         21 . The method according to  claim 17  wherein the method comprises milling in a downward direction. 
     
     
         22 . (canceled) 
     
     
         23 . The method according to  claim 1  wherein the method comprises pulling the tubing out of the casing if the cement bond is shown to be of poor quality. 
     
     
         24 . The method according to  claim 1  wherein the method comprises deploying a cement plug in the casing if the cement bond is shown to be of sufficient quality. 
     
     
         25 . The method according to  claim 1  wherein the method comprises assessing the quality of the cement of a second zone by running a tubing cutter tool in the tubing and cutting the tubing at an upper end of the second zone and dropping the cut tubing further downhole so that the second zone is exposed for assessment. 
     
     
         26 . The method according to  claim 1  wherein the method further comprises repeating the steps at one or more shallower depths in the well. 
     
     
         27 . (canceled) 
     
     
         28 . The method according to  claim 1  wherein the two or more steps are performed on the same trip into the well bore.